Wireline packoff for a downhole electrical tool

ABSTRACT

A method and apparatus is provided for hermetic sealing of a wireline and a termination housing. The primary electrical connection of a wireline termination is sealed within a fluid-filed packoff bore of a termination housing. Wireline release strength can be selected upon wireline connection. A sealed termination housing has an uphole mechanical structure or support for transferring wireline armor tensile loads to the sub, a packoff bore for housing the wireline electrical conductor at a primary electrical connection, and a downhole closure. An inherent leak path of pressurized well fluids into termination housing is blocked by a dielectric fluid pad therein that fills the packoff bore from the downhole closure end and to a location at or uphole of the electrical connection made between the wireline and a hermetically sealed electrical connection exiting the downhole closure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application62/893,510, filed Aug. 29, 2019, the entirety of which is incorporatedfully herein by reference.

FIELD

Embodiments herein relate to apparatus and methods for establishing themechanical and electrical integrity of a wireline to the tool, and moreparticularly to a fluid sealed termination apparatus and methodologytherefor.

BACKGROUND

Wireline operations are carried out in oil and gas wells for conveyingtools downhole in the well. A wide variety of downhole tools may besupported on a wireline including tools to perform logging, perforating,and setting and retrieving operations. Logging tools can be electricallycoupled to surface through one or more electrical conductors sheathedwithin armor about the wireline. The wireline armor has a limitedoperational tensile strength and for deeper or horizontal wells may becombined with a surrounding tubing string such as coil tubing forgreater tensile capability.

In either case, a cable head is provided which connects the wireline tothe downhole tools both for tensile and electrical connections. For awireline extending downhole through a tubing string, the cable head alsocan affect coupling to the tubing string. The wireline cable headconnection is also typically provided with a tensile release interfaceto permit the wireline to be disconnected from the tools, such as whenthe tools become stuck downhole. Wireline armor comprises strands ofindividual wires wound about the electrical connector. One or morelayers or wires may be provided, determining the operating tensilestrength of the wireline. The electrical conductor is typically coveredin an elastomeric insulator or cover.

With reference to FIG. 1A through FIG. 2B, in a known prior arttechnique for making a tensile connection, the wireline is passedthrough a restricted entrance bore into a packoff bore. The packoff boreis housed in a tool body, typically referred to as a cable head. Some orall of the individual wires of the wireline armor extend through theentrance bore, through a support bushing and are bent back upholethereabout. The support bushing is sized for the packoff bore but islarger than the entrance bore to prevent return of the bushing and armortherethrough, establishing the tensile connection. The number of wiresto bend back uphole predetermines the tensile release interfacecapability; the more wires, the higher the required release load. Theelectrical connector passes through the bushing for electricalconnection downhole.

A packoff arrangement is fit about the wireline passing through thepackoff bore downstream of the bushing in an attempt to exclude wellfluids. However, as is the nature of cables and armor for wireline, theannular wound, discrete and axially adjacent individual and cylindricalwires provide a leak path for fluids therealong which is difficult toseal. In downhole settings, with operational pressures, such as inhydraulic fracturing, pressures can reach in the order 15,000 psi, whichcauses fluid to creep along the small crevices between wires. Thus,while the industry has managed tensile load considerations, it has onlybeen partially successful in mitigating hydrocarbon and drill fluidingress into the connections of wirelines and tool electricalconnections.

The balance of the tool is integrated with the cable head or otherwiseremovably attached thereto, the tool having a cylindrical structuralbody for supporting electronics and conducting fluid passagestherethrough while bypassing the electronics. The body is fit with apressure barrel that is a removable tubular housing for covering theelectronics and providing connection access thereto. A side port in thebody is employed as an access, and connection chamber, for enablingat-surface termination of the wireline tensile connection and theelectrical connection. The side port is accessible when the tubularhousing is displaced axially for connection, exposing a chamber.

The wireline extends through the restricted entrance bore of an upholeend of the side port to the chamber and out of the packoff bore forfitting of the support bushing, seals and means for electricalconnection. The electrical conductor portion of the wireline is trimmedfor fitting with an electrical conductor extending into the chamber froma bulkhead fitting at a downhole end of the side port. The bulkheadfitting is sealably secured to isolate the electronics from the chamber.The supported and electrically connected wireline resides in theconnection chamber and is sealed by repositioning the tubular housingover the side port. The tubular housing is fitted with seals to excludewell fluids.

Accessed through the side port, the packoff bore receives the wirelinesupport bushing and packoff components for sealing between the wirelineand the body. Downstream of the support bushing is the packing or apackoff. The packoff typically comprises a series of seals includingcylindrical bushings having circumferential O-rings to seal to theentrance bore, and one or more plastic bushings that, when compressedaxially, expand radially to aid in sealing inwardly onto the wirelinearmor. In operation, the connection chamber is and remains atatmospheric pressure.

The electrical conductor portions extend into and are terminated in theconnection chamber.

As a result of the wireline characteristics and pressure differentialfrom the entrance bore and connection chamber, high pressure fluids inthe wellbore migrate under differential pressure along the packoff tothe low pressure connection chamber. Fluids can flow along the armorstrand interfaces of the wireline, penetrating the bulkhead to wirelineconnection, and result in a failed connection.

Vulnerability to fouling or contamination of the electrical connectionis a persistent cause of sensor tool operation and communicationfailure. Further, the arrangement of the packoff components andelectrical conductor termination requires handling of many componentsand steps requiring skill and time, often resulting in error.

In addition, as previously stated, a wireline cable head connection isalso typically provided with a tensile release interface. The restrictedbore entrance provides the tensile connection of the wireline and thedownhole tool components. With prior technology as shown in publishedapplication WO2004046497A1, a commonly accepted safe operational pull ofthe wireline is a pull which does not exceed one-half the breakingstrength of the wireline. When a tension is placed on the wireline whichis over 50% of its break point, then problems begin to occur with theelectrical conductors in the wireline. Also, there is the danger ofbreaking the wireline.

A typical wireline release utilizes a mechanical weak point in theconnection made between the wireline and the cable head. Typically thisis a metal member which is designed to break, like a fuse analog,breakable upon a predetermined pull force on the wireline. The correctconventional mechanical weak point must be calculated and installedprior to running the cable head and tools into the borehole on thewireline.

There are two limitations in using the typical mechanical weak pointrelease, one is the strength of the wireline itself and the other is thestrength of the mechanical weak point. For example, when the tool isstuck, the operator will fish for the tool with the wireline stillattached to the tool in the hole. The operator lowers a grapple on aseparate line, such as a slick line, which grabs the top of the cablehead or the tool body. Once the tools are engaged by the grapple, theoperator can release the wireline from the tool and remove it from thehole. Removing the wireline makes it easier to pull the tools and pipeout of the well. In order to affect the release, the operator places alarge tension on the wireline to activate the typical mechanicalrelease.

There is interest in the industry for a robust and releasable apparatusand methods for coupling wireline and downhole tools, including methodsof reliably terminating electrical conductors and sensor tools.

SUMMARY

In an embodiment, the primary electrical connection of a wirelineterminates, and thus is wholly enclosed and sealed, within a closedpackoff bore of a termination housing. The termination housing can beformed within a cable head, a downhole tool itself or other intermediatepackoff or termination sub. The wireline release strength can beselected upon wireline connection.

In any event, the termination sub is sealably coupled or integrated withan uphole end of the downhole tool carrying the electrical components.Such a downhole tool includes a sensor tool. The packoff sub includesthe sealed termination housing having an uphole mechanical structure orsupport for transferring wireline armor tensile loads to the sub, apackoff bore for housing the wireline electrical conductor at a primaryelectrical connection, and a downhole closure for sealing the packoffbore from fluid flow therethrough.

The wireline conductor, or conductors, extend downhole from the armorand end within the sealed packoff bore. Thus, any wellbore fluidpenetration is stopped thereat, including possible seepage or leakagedownhole along the wireline and through the otherwise sealed packoffbore.

A secondary electrical connection or interface, such as a hermeticallysealed electrical pass-through connector, extends sealably from thepackoff bore's downhole closure end. A downhole end of the secondaryelectrical connection enables releasable electrical coupling with thedownhole tool or sensor. An uphole end of the secondary electricalconnection enables releasable electrical coupling with the electricalwire of the wireline conductor.

The wireline conductor terminates at an electrical connection within thesealed packoff bore. The only available leak path of well fluids is intothe packoff bore at the entrance of the wireline. Under well pressures,well fluids are known to leak along the wireline armor and aboutcomponents therein and deep into the packoff bore. To prevent well fluidfrom migrating therealong and to the primary electrical connection, thepackoff bore is filled with a fluid pad, such as dielectric grease, toform a substantially incompressible liquid front or barrier that fillsthe packoff bore from the downhole closure end and at least uphole ofthe electrical connection. The dielectric grease cannot be displaced byfluid and therefore prevents ingress of well fluids thereto. Inembodiments, to minimize or eliminate air pockets, the components can beassembled pre-greased. In further embodiments, to displace air pocketsabout the primary electrical connection, grease is injected from thedownhole ends and displaced uphole to minimize air pockets and voids.

Access for fluid pad to the sealed packoff bore is provided via aclosable fluid pad port. The injected grease is directed into thetermination housing to flow uphole within the packoff bore from thedownhole closure end, about the packoff components, and along the bore,at least to encompass the electrical connection. Where the grease iscontinuous within the packoff bore, wellbore fluids are excluded. Thegrease fills the cross-section of the packoff bore from its downhole endand uphole to the extent needed to exclude the ingress of wellbore fluidto the primary electrical connection, despite the possibility of somevoidage and grease installation deficiencies.

Uphole of the primary electrical termination, excess injected grease, ifany, flows along the packoff bore and wireline leak path and candischarge at the uphole end of the termination housing.

In an embodiment, a boot housing resides in the packoff bore and housesthe primary electrical connection and a secondary electrical connectionpassing through a packoff bulkhead at the downhole end of the boothousing. An elastomeric boot is provided about the electrical insulationof the wireline conductor uphole of the electrical contact and is housedwithin the boot housing. Dielectric grease can be pre-placed into theboot to minimize air pockets or voids including along the interface ofthe grooved or impressed insulation jacket about the wire, theimpressions resulting from the inner strands of the wireline.

In an embodiment, access to the fluid pad need not be located at thedownhole closure end to affect the fluid pad. The boot housing furthercomprises one or more grease galleries to receive grease injectedthrough the termination housing and direct it firstly to an extremedownhole location within the boot housing before entering the packoffbore to fill voids and displace undesirable bore fluids uphole whilebeing backfilling with the grease. Secondly, grease can be directedalong the interface between the packoff assembly and the packoff bore.Circumferential seals, such as O-rings, can be located between the boothousing and the packoff bore at the uphole and downhole ends of the boothousing for preventing the passage of grease and fluids thereby.

The boot housing can receive an uphole source of grease through thepackoff housing, distribute it about the circumference through the oneor more grease galleries, and controllably direct the grease to anextreme downhole location before discharge into the packoff bore. Thedownhole end of the boot housing forms the packoff bulkhead at thedownhole end of the packoff bore once secured therein. The housing'sdownhole end also supports the hermetically-sealed secondary electricalconnection that projects downhole of the packoff bulkhead of the sealedpackoff bore. The injected grease can complete backfilling of anydielectric grease preplaced in the packoff bore and elastomeric boot,thus eliminating any voids in the grease pad.

In one method of installation and termination of the wireline, thewireline is extended downhole through uphole mechanical support of thepackoff housing and at least some of the armor is wrapped back upholeabout a support bushing fittable within the packoff bore, to bearagainst the entrance structural support, for transferring wireline armortensile loads to the uphole support. In embodiments, the uphole supportmay be integral with the packoff housing, or in alternate embodiments,the uphole support is releasably secured to the packoff housing with anuphole stop imparting fuse characteristics.

The wireline is passed downhole through a restricted entrance bore andthrough a bore in the support bushing, such as a cone-like bushing. Someor all of the individual wires of the wireline armor extending downholethrough the support bushing bore are bent back uphole thereabout. Thesupport bushing is larger than the entrance bore. The wireline, bentwires, and support bushing are secured concentrically within an annularsurrounding housing, so that under tension, the support bushing and bentwires are supported radially and prevented from releasing from about thesupport bushing and thus enabling a tensile connection therebetween. Thenumber or wires to bend back uphole predetermines the tensile releaseinterface capability of the wireline portion; the more wires, the higherthe required release load. The uphole stop also provides a means offused release.

A non-supportive remaining wireline portion, comprising at least theelectrical conductor, itself comprised of the wire and insulative orinsulating jacket, extends downhole from the support bushing and intothe packoff bore. As is the nature of cables and armor for wireline, theindividual wires inherently provide a leak path for fluids therealong,that path being difficult to seal. In downhole settings, withoperational pressures, such as in hydraulic fracturing, pressures canreach in the order 15,000 psi. Thus, the industry has had to addressboth the tensile load considerations whilst minimizing hydrocarbon anddrill fluid ingress to the connections of wirelines and tool electricalconnections.

In the prior art, as described above, a bushing was compressed tominimize the flow path along the radial extent of the interface betweenthe bore of the bushing and the wireline armor wire strands. The use ofsuch a bushing was unsatisfactory, as fluid was still capable of leakingalong the wireline armor strands under high pressure due to the smallradial spaces that exist between the wireline armor and the bore of thebushing.

Herein, in an embodiment, a compressible packoff sealing bushing mayalso be installed, as was the case in the prior art, about the remainingwireline portion for restricting the annulus formed between the wirelineand packoff bore. While the migration of well fluid is restricted by thepackoff bushing, it is not eliminated. However, in the currentembodiments, the termination arrangement also incorporates a grease padto prevent well fluid from contaminating the electrical conductor of thewireline.

The electrical conductor extends from the support bushing and packoff,if so fit, and is fit at its termination with an electrical contacthaving a female receptacle. A further and hermitically sealed electricalconnector is supported at, and through, a downhole electrical bulkhead.An uphole electrical pin, in the packoff bore, is releasably coupledwith the electrical contact.

Between the packoff bushing and the downhole electrical bulkhead is agrease recess. The electrical bulkhead or a closure cap secures thebulkhead to the packoff bore, compressing the packoff seal against theuphole support. Grease is injected into the grease recess, at about thedownhole electrical bulkhead, for displacement uphole along the packoffbore to form an axial barrier at least at or uphole of the electricalcontact. A downhole electrical pin extends from the downhole electricalbulkhead for releasable coupling with the downhole tool. In operation,well fluid at operating pressures can only ingress through the upholesupport and along the wireline until reaching the fluid pad formed bythe axial fluid barrier formed by the injected grease.

In an embodiment, the packoff seal is a tubular seal assembly thatcouples with the support bushing, and the downhole bulkhead is a tubularbulkhead component that couples with the packoff seal for forming atubular packoff assembly that is insertable into the packoff bore forretention against the uphole support, the assembly being retainedtherein by a downhole closure.

In one embodiment of method of termination, the wireline isover-extended through the packoff bore and the tubular packoff assemblyis assembled downhole of the packoff bore. The wireline and assembledpackoff assembly is pushed back a short distance uphole into the packoffbore to bear against the uphole support and the closure plug nut securesthe assembly therein. The grease port is uncovered, temporarily fit witha fitting and grease is injected to establish the fluid barrier. Thebalance of the tool is electrically coupled to the downhole electricalpin extending from the closure.

In an embodiment, the packoff assembly includes serially threadablecomponents. To enable threadable coupling of the components,conveniently and temporarily outside of the packoff bore, the downholeend of the packoff bore is compatible with the fitting of a temporaryvise for non-rotatable retention of uphole components during assembly ofsequential downhole components. The vise is removable thereafter forinsertion and securing within the packoff bore.

In a method of assembly, the wireline can be readily connected to acable head or termination sub in a dependable, reliable, andelectrically sound manner. For replacing the packoff bore or installinga new wireline, the termination sub is decoupled from the downhole toolto expose the packoff bore and the packoff assembly is removed from thepackoff bore. The packoff bore components are uninstalled from thedistal end of the wireline.

Thereafter and for an initial assembly, the wireline is introducedthrough the restricted entrance of the uphole support of the packoffbore. For convenience of external assembly of the packoff assembly, ananchor slip vise can be secured about the downhole end of the packoffbore.

The wireline is installed through a restricted uphole support of apackoff bore of the cable head and extending the wireline out a downholeopening. The anchor slip is temporarily secured to the packoff boreadjacent the downhole opening. At least an outer armor of the wirelineis separated and bent back uphole over the anchor slip, the number ofstrands predetermined for setting the tensile release force of thewireline to the packoff assembly. The bent strands are trimmed and atubular cap installed thereover to trap the bent strands in an annulusformed therebetween. The cap is axially secured to the anchor slip. Theremaining wireline extends downhole and the remaining armor trimmedadjacent the cap to expose the remaining wireline conductor.

A packoff bushing is fit to the wireline, sandwiched between an upholeconical recess and a downhole conical recess, wherein, when axiallycompressed therebetween, the bushing compressively engages the remainingwireline, a portion of wireline conductor extending downhole of thepackoff bushing.

A primary releasable electrical connector contact is electricallysecured to the wireline conductor wire. A secondary electricalconnector, sealably secured at a packoff bulkhead, is coupled to theprimary electrical connector contact.

The wireline, anchor slip and cap, bushing, and electrical connectorsare installed into the packoff bore sealed therein by a closure plug,the packoff bore being fluidly sealed. However, the secondary electricalconnector is electrically passed through the downhole end of the packoffbore before electrical coupling with the downhole tool.

In embodiments, and before installation into the packoff bore, any orall of one or more groups of components can be pre-assembled. A firstgrouping of the anchor slip and cap can be threadably coupled, a secondgrouping of the uphole conical slip, bushing, and downhole conical slipcan be threadably coupled, a third grouping of the secondary electricalconnector and bulkhead can form a unitary group, and each of the first,second, and third groups can be threadably coupled to one or severalpackoff cartridges. Each independent group and the group couplings canbe provided with manual inclusion of dielectric grease. Any or all ofthe groups can be injected with pressurized grease.

After the packoff assembly is installed and sealed within the packoffbore, pressurized grease is injected at the downhole end of the packoffbore, at the secondary electrical connector bulkhead for displacing thebore volume, such as remaining air or other voids, uphole until padgrease backfills the packoff bore at least uphole of the primaryelectrical connection for forming a barrier to leakage of well fluidsfrom the restricted entrance bore and along the wireline passingtherethrough, preventing the well fluids from reaching the electricalconnection(s) between the wireline conductor and tool.

In one aspect, a method is provided for sealing a wireline in a cablehead located between the wireline and a downhole tool, the wirelinehaving wireline armor and an electrical conductor therealong, the methodcomprising: inserting the wireline through an uphole stop of a packoffbore of the cable head and out of a downhole opening of the packoffbore; positioning an anchor slip about the wireline; bending one or morewires of the armor over a slip interface of the anchor slip and securingthe one or more wires to the anchor slip. Further, a packoff bushing ispositioned about the wireline downhole of the anchor slip and electricalcontact is established by electrically connecting the conductor of thewireline with a boot contact to form a primary electrical connection;coupling a first contact of a feed-through connector with the bootcontact to form a secondary electrical connection; and inserting thefirst electrical and second electrical connections into a boot housing,the anchor slip, packoff bushing, and boot housing forming a packoffassembly. The packoff assembly is inserted into the packoff bore andfurther comprises: sealing the downhole opening of the packoff bore witha closure nut; and introducing grease to the packoff bore such thatgrease fills the packoff bore from the downhole end to encompass atleast the primary electrical connection and the secondary electricalconnection.

In another aspect, a cable head termination sub comprises: a cable headhaving a structural body, the body having a packoff bore extendingtherethrough from an uphole end of the body to a downhole end of thebody, the downhole end adapted for releasable coupling with the tool;and the packoff bore being configured to releasably receive a packoffassembly therein and having an uphole stop defining an entrance bore,and a downhole opening, the entrance bore having an entrance diametersmaller than a bore diameter of the packoff bore and sized for receivingthe wireline therethrough. A closure plug is provided for sealing thedownhole opening and fluidly isolating the packoff bore from thedownhole tool; and a grease port located on the body for introduction ofdielectric grease to the packoff bore. The packoff assembly comprises:an uphole anchor slip having a slip bore for receiving the wirelinetherethrough and a slip interface for securing the wireline armorthereto, the anchor slip bearing against the uphole stop; a packoffbushing downhole of the anchor slip having a bushing bore for receivingthe wireline therethrough; a boot contact attached to the wirelineconductor to form a primary electrical connection; and a feed-throughconnector having a first contact compatible with the boot contact andcoupled thereto to form a secondary electrical connection, and a secondcontact for electrical connection with the downhole tool; and when thepackoff assembly is sealed within the packoff bore with the closureplug, the grease within the packoff bore prevents fluid from reachingthe first and second electrical connections.

In a broad aspect, a cable head termination sub is located between awireline having wireline armor and an electrical conductor therealong,and a downhole tool, the termination sub comprising: a cable head havinga structural body, the body having a packoff bore extending therethroughfrom an uphole end of the body to a downhole end of the body, thedownhole end adapted for releasable coupling with the tool; and thepackoff bore configured to releasably receive a packoff assembly thereinand having an uphole stop defining an entrance bore, and a downholeopening, the entrance bore having an entrance diameter smaller than abore diameter of the packoff bore and sized for receiving the wirelinetherethrough; a closure plug for sealing the downhole opening andfluidly isolating the packoff bore from the downhole tool; and a greaseport located on the body for introduction of dielectric grease to thepackoff bore; and wherein the packoff assembly comprises an upholeanchor slip having a slip bore for receiving the wireline therethroughand a slip interface for securing the wireline armor thereto, the anchorslip bearing against the uphole stop; a packoff bushing downhole of theanchor slip having a bushing bore for receiving the wirelinetherethrough; a boot contact attached to the wireline conductor to forma primary electrical connection; and a feed-through connector having afirst contact compatible with the boot contact and coupled thereto toform a secondary electrical connection, and a second contact forelectrical connection with the downhole tool; and when the packoffassembly is sealed within the packoff bore with the closure plug, thegrease within the packoff bore prevents fluid from reaching the firstand second electrical connections.

In an embodiment, the grease port directs grease to the downhole end ofthe packoff bore for backfilling the packoff bore with the grease fromthe downhole end toward the uphole end.

In an embodiment, the packoff assembly first comprises a boot housinghaving a downhole end sealably supporting the secondary electricalconnection at the closure plug, an uphole end for receiving the primaryelectrical connection, and a boot having an uphole boot end fitconcentrically about the wireline conductor and the boot contact and adownhole boot end for releasably receiving the first contact when thefirst contact is coupled with the boot contact, the boot residing withinthe boot housing.

In an embodiment, the boot housing has at least a first grease galleryadapted to direct injected grease from the grease port at least downholeto the downhole end of the packoff bore.

In an embodiment, the boot housing further comprises a circumferentialseal for creating a seal with the packoff bore uphole of the grease portfor preventing grease from travelling uphole between the boot housingand packoff bore.

In an embodiment, the boot housing has at least a second uphole galleryadapted to direct grease toward the uphole end of the packoff bore andalong an annulus defined between the packoff assembly and the packoffbore.

In an embodiment, the boot housing further comprises an uphole port fordischarging grease along the annulus.

In an embodiment, the uphole stop is removably coupled with the packoffbore.

In another broad aspect, a method is provided for sealing a wireline ina cable head located between the wireline and a downhole tool, thewireline having wireline armor and an electrical conductor therealong,the method comprising: inserting the wireline through an uphole stop ofa packoff bore of the cable head and out of a downhole opening of thepackoff bore; positioning an anchor slip about the wireline; bending oneor more wires of the armor over a slip interface of the anchor slip andsecuring the one or more wires to the anchor slip; positioning a packoffbushing about the wireline downhole of the anchor slip; electricallyconnecting the conductor of the wireline with a boot contact to form aprimary electrical connection; coupling a first contact of afeed-through connector with the boot contact to form a secondaryelectrical connection; inserting the first electrical and secondelectrical connections into a boot housing, the anchor slip, packoffbushing, and boot housing forming a packoff assembly; inserting thepackoff assembly into the packoff bore; sealing the downhole opening ofthe packoff bore with a closure nut; and introducing grease to thepackoff bore such that grease fills the packoff bore from the downholeend to encompass at least the primary electrical connection and thesecondary electrical connection.

In an embodiment, the method further comprises the step of securing theuphole stop within the packoff bore.

In an embodiment, the step of introducing grease to the packoff borefurther comprises directing the grease first to a downhole end of thepackoff bore and then toward an uphole end of the packoff bore.

In an embodiment, the method further comprises the step of applyinggrease to one of the anchor slip, packoff bushing, and boot housing, ora combination thereof, prior to sealing the downhole opening of thepackoff bore.

In an embodiment, the step of inserting the first and second electricalconnections into a boot housing further comprises inserting the firstand second electrical connections into a boot and inserting the bootinto the boot housing.

In an embodiment, the step of positioning the anchor slip furthercomprises securing a vise to the wireline downhole of the downholeopening and coupling the anchor slip to the vise, and step of insertingthe packoff assembly into the packoff bore comprises first removing thevise from the wireline.

In an embodiment, grease is introduced to the downhole end of thepackoff bore.

In an embodiment, the grease is introduced at an axial location upholeof the downhole end of the packoff bore, the grease flowing toward thedownhole end via at least a first grease gallery.

In an embodiment, the method further comprises directing the greasetoward the uphole end from the downhole end via at least a second greasegallery.

In another broad aspect, a packoff assembly is provided for use within apackoff bore of a cable head to connect a wireline having wireline armorand an electrical conductor therealong with a downhole tool, comprising:an uphole anchor slip having a slip bore for receiving the wirelinetherethrough and a slip interface for securing the wireline armorthereto; a packoff bushing having a bushing bore for receiving thewireline therethrough; a boot housing having a feed-through connectorsealably supported therein, the feed-through connector having a firstcontact compatible with a boot contact attached to the wirelineconductor and a second contact for electrical connection with thedownhole tool; and at least a first grease gallery formed in the boothousing and adapted to receive grease injected into the packoff bore anddirected the grease towards a downhole end of the boot housing.

In an embodiment, the boot housing defines an uphole port incommunication with at least a second grease gallery and adapted todirect grease toward an uphole end of the packoff bore and along anannulus defined between the packoff assembly and the packoff bore.

In an embodiment, the boot housing comprises a boot having an upholeboot end fit concentrically about the wireline conductor and the bootcontact a downhole boot end for releasably receiving the first contactwhen the first contact is coupled with the boot contact, the bootresiding within the boot housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1C illustrate a prior art tool and wireline to tooltermination according to Applicant's patent application WO2018137027published Feb. 8, 2018 from PCT/CA2018/050080, the entirety of which isincorporated herein by reference, the tool having a cable head packoffsub for connection to the wireline and optionally to coil tubing, asensor tool for electrically and fluidly coupling to the packoff sub,and a sealing tubular or pressure barrel for fluidly sealing thewireline termination connection chamber and sub to the tool coupling;

FIG. 1A is a cross-sectional view of the prior art uphole cable headpackoff sub coupled to a downhole sensor tool;

FIG. 1B is an enlarged cross-sectional view of the uphole cable headportion of the tool of FIG. 1A, and illustrating the pressure barrelhaving been displaced axially downhole for access to the terminationconnection chamber and a packoff bore in the packoff sub having awireline extending therethrough prior to termination, the packoff borebeing fluidly connected to the connection chamber;

FIG. 1C is a cross-sectional and exploded view of the prior art packoffcomponents as they are installed about the wireline of FIG. 1B;

FIG. 2A illustrates the cross-sectional view of the prior art packoffbore of FIG. 1B with some of the packoff components being guided ontothe wireline for installation into the packoff bore about the wireline,the components including an uphole stop, a wireline anchor cap, anuphole packoff bushing, and a grease gallery;

FIG. 2B is a cross-sectional view of the prior art packoff bore of FIG.2A, the tubular housing having been removed, with all of the packoffcomponents within the packoff bore and compressibly secured therein by apackoff nut, the electrical conductor terminated at an electricalcontact and termination arrangement within the termination connectionchamber for extending sealably through a pressure bulkhead of the sensortool of FIG. 1A;

FIG. 3 is a perspective view of one current embodiment of a cable headpackoff sub, a packoff assembly, and a packoff-to-sensor tool adapter,the packoff assembly having a simplicity of assembly and having a sealedtermination of the wireline electrical conductor within;

FIG. 4 is a perspective view of an embodiment of a sensor tool with apressure barrel removed to access to the electronic components, theuphole end fit with a target ring (shown displaced uphole from the tool)for enabling coupling of the electrical components between the wirelinepackoff sub and the sensor tool;

FIG. 5 is a cross-sectional view of a clean packoff sub body, free ofwireline packoff components, the body rotationally oriented with thepackoff bore shown below the flow passage thereabove, the packoff borereceiving the wireline from the uphole end at the left and is closed andfluidly sealed at the downhole end at the right;

FIGS. 6A, 6B and 6C respectively illustrate a side, uphole, and downholeend view of the packoff sub of FIG. 5, repeated in smallerrepresentation in side view in FIG. 6A, the downhole end view shown inFIG. 6B, and the uphole end view shown in FIG. 6C;

FIG. 7 is a side cross-sectional view of an embodiment of the packoffcomponents, assembled into a packoff assembly or cartridge forinstallation within the packoff bore of FIG. 5 and for sealing thedownhole end of the packoff bore when secured therein, and in thisembodiment, the cartridge bearing again an uphole packoff stop installedin the packoff sub from the uphole end thereof and the remainder of thecomponents installed into the packoff bore from the downhole end, thepackoff components being sealably and compressed therein by a downholeclosure nut or plug;

FIG. 8A illustrates a cross-sectional and exploded side view of thepackoff components installed about a wireline, the wireline shown brokenperiodically therealong to better illustrate the structure of thecomponents;

FIG. 8B is a cross-sectional and exploded side view of the wirelineconductor termination to a sealed conductor, the conductor terminationhaving a protective boot thereabout, all of which resides within thepackoff bore;

FIG. 8C is an exploded perspective view of the packoff components forinstallation into the packoff bore including the uphole stop forsecuring into the uphole end of the packoff bore;

FIG. 8D is a cross-section of an embodiment of a boot housing cut at 90degrees to illustrate the section through one of two opposing axialstructural stringers and one side opening of two opposing side openings,the stringer connecting the uphole end to the downhole packoff bulkheadend;

FIG. 9A is repeat of the body of the packoff sub, rotated about the bodyaxis to present the packoff bore at the top in an orientation convenientfor installation and assembly of the wireline packoff, the flow passagearranged therebelow;

FIG. 9B is a repeat of the packoff components of FIG. 7, the componentsarranged juxtaposed axially from the packoff bore of FIG. 9A, in whichthey are to be installed;

FIG. 9C illustrates the packoff sub of FIG. 9B with a distal end of awireline extending through the packoff bore, the wireline shown in itspost-packoff installation form with one or more of the wireline armorwires bent back uphole;

FIG. 10 is a cross-sectional side view of the packoff sub with thepackoff components installed therein, the uphole stop installed fromuphole end of the packoff bore and the balance of the componentsinstalled from downhole end, the wireline shown trimmed according toFIG. 9C;

FIG. 11A illustrates an end view of the downhole end of the packoff subwith a temporary wireline vise secured thereto by two diametricallyopposed cap screws (not detailed);

FIG. 11B illustrates a cross-sectional side view of the downhole end ofthe packoff sub with the temporary wireline vise secured thereto;

FIG. 11C is a cross-sectional side view of a wireline anchor slip andwireline securing Allen screw poised thereabove, the anchor slip beingspaced axially from the vise shown in FIG. 11B for insertion into thevise and rotationally constrained therein;

FIG. 11D is an uphole end view of the wireline anchor slip forillustrating the hexagonal profile for mating with a hexagonal socket ofthe vise for locking thereto rotationally and clamped axially when thevise is damped thereto;

FIG. 12A illustrates a cross sectional side view of the packoff sub ofFIG. 9B with a distal end of a wireline extending firstly through theuphole stop and then extending through the packoff bore;

FIG. 12B is an exploded perspective view of the remaining packoffcomponents for installation into the packoff bore from the downhole endthereof, the wireline passing through the anchor slip, some or all ofthe armor wires bent back uphole and thereabout for forming the tensileconnection and the balance of the wireline extending through the packoffbore to terminate at the electrical connection;

FIG. 13A illustrates a cross-sectional side view of the packoff sub ofFIG. 12A with all components installed and the packoff bore sealed atthe closure cap. Further, the path of the pre-charging pad grease isshown via arrows, the grease introduced from a temporary grease nippleand using the boot housing as a grease gallery to conduct the grease tothe downhole most location in the packoff bore for displacement upholealong the wireline;

FIG. 13B is a perspective and exploded view of the wireline conductortermination to the sealed conductor, and as shown from the uphole end,the termination having a crimp-on female contact, a protective boot, aplastic boot support sleeve, the sealed electrical connector having amale uphole and downhole ends, an uphole O-ring for the boot housing,the boot housing, and downhole seals, the downhole end of the boothousing forming a packoff bulkhead for sealably passing the secondaryand hermetically sealed electrical connector;

FIG. 13C illustrates a cross-section of the wireline with two layers ofarmor, a conductor wire, and conductor insulating jacket between thearmor and the conductor;

FIG. 13D illustrates a cross-section of the protective boot of FIG. 13Binstalled about the conductor wire and conductor insulating jacket ofFIG. 13C, the boot only partially conforming with the scallopeddeformations on the outside of the insulation;

FIG. 13E illustrates a cross-section of the protective boot of FIG. 13Bover a side view of the conductor wire and conductor insulating jacketof FIG. 13C and illustrating the boot only partially conforming with thescalloped deformations on the outside of the insulation;

FIG. 14 illustrates a cross-sectional side view of the packoff sub ofFIG. 13A, with the packoff sub housing extended so as to axiallyposition the grease port corresponding with the downhole-most locationof the packoff bore without the need for a grease gallery in the of FIG.13A;

FIG. 15A illustrates a cross sectional side view of the packoff sub ofwith an alternate embodiment of the packoff components installed, thecomponents stacking sequentially but not in a self-supporting cartridgeformat;

FIG. 15B illustrates a cross sectional side view of the packoffcomponents installed in the packoff bore of FIG. 15A, and components notnecessarily being secured to one another, but being serially stackableand having full bore diameter, the wireline armor anchor cap being fitto the bore, the uphole and downhole cone stops being full bore diameterand the bushing sized accordingly;

FIGS. 16A through 30A illustrate the steps to terminate a wireline in anembodiment of the cable head according to FIG. 3;

FIG. 30B illustrates a quality control viewing of the resultingincompressible grease filled packoff cartridge resulting therefrom;

FIGS. 31A through 31D illustrate an embodiment of the steps needed toterminate a wireline in a termination sub using apparatus and methodsdisclosed herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS General Overview

In embodiments, and as shown in FIGS. 9A to 10, a wireline 10 issupported and terminated in a termination sub 24. With reference toFIGS. 13C to 13E, the wireline 10 comprises wireline armor 12 and atleast one electrical conductor 20. The wireline armor 12 comprisesnumerous armor strands or wires 14, and can be supportably connected tothe termination sub 24 to create the tensile connection with the sub 24.The electrical conductor 20 is terminated and sealed within thetermination sub 24.

With reference to FIGS. 3, 4, and FIGS. 31A to 31D, one process 200 isshown for termination and electrical connection of a wireline 10 to asensor tool 22. At step 202, a termination sub 24, such comprising as acable head 30 and adapter assembly 26, is disconnected from the sensortool 22, exposing the termination sub 24 for accessing a packoff bore 32extending through the body thereof. Depending upon the stage at whichthe termination is performed, whether to affix a wireline 10 in thefirst instance or for replacement thereof, various additional or fewersteps may apply.

As best shown in FIGS. 5 to 6C, cable head 30 can comprise a generallytubular body having a packoff bore 32 for terminating and electricallyconnecting the wireline 10 and a flow bore 38 for permitting fluidcommunication therethrough without interference with the componentshoused in the packoff bore 32.

As shown in FIGS. 16A and 168, at step 204, in the instance that a cablehead 30 and adapter assembly 26 have just been separated from a sensortool 22, the adapter assembly 26 is exposed and can be separated fromthe cable head 30. As shown in FIGS. 3 and 4, the adapter assembly 26,and corresponding adapter target ring 28, couples the termination sub 24to the sensor or other downhole tool 22 as the situation dictates.

Returning to FIG. 16A, fasteners, such as a pair of cap screws, areremoved and the freed adapter assembly 26 is removed axially from thedownhole end 36 of the cable head 30 for separating the sealed flowpassage coupling from the adapter 26, exposing the packoff bore 32, anddisconnecting the downhole electrical connection pin of the packoffcartridge 40 from the female electrical connection plug of the adapterassembly 26.

As shown in FIG. 17A, pulling the adapter assembly 26 exposes thepackoff bore 32. A previously installed packoff assembly cartridge 40may already be installed in the packoff bore 32. If so, the closure plugnut 42 of the prior installation is removed and the packoff cartridge 40is removed. The closure plug nut 42 is engageable with a wrench. Thedownhole end can be castellated or fit with an array of wrench recesses,such as pin holes 43, for enabling engagement and unthreading of theclosure plug nut 42 from the threaded downhole end 36 of the packoffbore 32. The packoff cartridge 40 is then available for extraction fromthe packoff bore 32 (step 206). A puller tool (not shown) can bethreaded onto the downhole end of the boot housing 94 for applying axialremoval loads.

Assuming the prior packoff cartridge 40 was removed, or not present, thepackoff bore 32 is available for a new or refurbished packoff cartridge40.

With reference to FIGS. 7 to 8C and 12B, and as will be explained ingreater detail below, the packoff cartridge or packoff assembly 40comprises numerous components for creating a tensile connection betweenthe cable head 30 and wireline 10, establishing an electrical connectionwith the wireline 10, and preventing wellbore fluids from coming intocontact with the electrical connection(s) made with the wirelineconductor 20.

As shown in FIG. 12A, an uphole stop 44, which can be integrated withthe cable head 30 or removably secured to the cable head 30, such as athreaded uphole stop 44, remains in place or is secured at the upholeend 34 of the packoff bore 32. The uphole stop 44 acts as a fuse,retaining the wireline 10 in the packoff bore 32 as long as the tensileload thereon is below a threshold, and releasing like a fuse if thethreshold tensile load is exceeded. The distal end of the wireline 10 isshown in juxtaposition with the cable head 30 as it would look wheninstalled in tensile connection and with electrical terminationcomplete.

The installable and releaseable uphole stop 44 is a fuse having apredetermined failure strength that permits the mechanical weak pointrelease to be selected upon installation of the wireline 10 to the cablehead 30. Accordingly, the strength of the mechanical weak point can beadjusted separate and apart from the cable head 30 or wireline 10themselves.

As shown in FIGS. 8A and 17A, at step 208, a wireline 10 having a new orraw cut end is extended through the restricted entrance 46 of the upholestop 44 and through the open packoff bore 32 to project from thedownhole end 38 thereof.

As shown in FIGS. 11A-11D and 17, at step 210, in order to facilitateassembly of the packoff cartridge 40, for post-assembly insertion of thecartridge 40 the packoff bore 32, a jig or vise 48 is temporarilysecured to the downhole end 36 of the cable head 30. The vise 48 issecured to the cable head 30, conveniently using the same fasteners orfastener locations that were used to secure the adapter assembly 26 tothe cable head 30. The vise 48 forms a polygonal clamp that grips thepolygonal uphole end 52 of an anchor slip 50. The vise 48 is alignedwith the packoff bore 32. The vise 48 also establishes the axiallocation of the wireline relative to the cable head 30 and to thecartridge 40.

As shown in FIG. 18A, at step 212, the anchor slip 50 is slipped over,or fit to, the protruding wireline 10. In the instance of a wireline 10within coil tubing 8, the coil tubing 8 is secured to the cable head 30such as through a dimple connector (not shown) uphole of the cable head30. The wireline 10 extends from the coil tubing 8 and through the cablehead 30 and results again as shown in FIG. 17A. The wireline 10, being aflexible cabling, can become serpentine when axially compressed orretracted into the coil tubing 8 and thus has the capability of alimited axial extension when pulled therefrom. To enable handmanipulation of the wireline 10 by personnel, the limited extension andretraction is managed during termination.

At step 214, the protruding wireline 10 is pushed back into the cablehead 30 against increasing resistance and the wireline 10 is marked. Thewireline 10 is pulled out of the cable head 30 to a working length,being less than a full by-hand extension. The anchor slip 50 can be slidonto the wireline 10 before or after the wireline 10 is cut off. Thewireline 10 is cut off at some convenient location greater than themarked location and about 8″ from the end of the anchor slip 50. Thewireline 10 can be cut at any other suitable location depending on therequirements of the operation.

As shown in FIG. 18A, at step 216, the anchor slip 50 is secured to thewireline 10 by tightening a set screw 58 once engaged with the vise 48(FIG. 18B) or with the anchor slip 50 spaced in close proximity to thevise 48. Also detailed in FIGS. 11A through 11D, at step 218, the clampportion of the vise 48 is tightened to pinch the anchor slip 50 andsecure the slip 50 axially and rotationally. Prevention of rotation ofthe anchor slip 50 and added components is aided by correspondinghexagonal or other irregular profiles in the vise clamp bore 49 anduphole end 52 of the anchor slip 50, here illustrated as a hexagonalprofile.

The anchor slip 50 forms the axial tensile connection of wireline 10 andcable head 30. The anchor slip 50, when installed to the packoff bore32, bears against the uphole stop 44, transferring tensile loads to thecable head 30 and thus to the downhole tool 22 connected downholethereof. The uphole stop 44 can act as a mechanical fuse, having apre-determined release or failure load to permit emergency release ofthe wireline 10 from the cable head 30 and enable retrieval of thewireline 10.

As shown in FIG. 18C, the anchor slip 50 has a small outer diametertubular slip interface portion 56 about which wireline armor wires 14can be bent back uphole thereabout.

In FIGS. 19A and 19B, the illustrated wireline 10 has at least twolayers of wound wire 14, the outermost wires 14 being separated at thecut end of the wireline 10, and bent back over the slip 50. Depending onthe design tensile loading, one can bend back some (lower tensilecapability) or many of the armor wires 14 (higher tensile capability),cutting those strands off flush with the end of the slip 50 that werenot so manipulated. As shown in FIG. 19B, for each one wire 14 beingbent back, two are shown being cut off, only using about ⅓ of theavailable wires from the outer armor 12 for an embodiment of theanticipated wireline tensile release strength.

As shown in FIG. 20C, at step 220, the wireline outer armor 12 ismanipulated to form a slip portion 12 a, and inner armor portion 12 b isshown projecting downhole thereof and may or may not be used for tensilesupport over the slip 50, or for sealing by the packoff bushing 70.Downhole of the armor 12 is the electrical conductor 20 portioncomprising the wire(s) and a conductor insulation layer or jacket 16.

As shown in FIG. 20A, at step 224, the armor wires 14 can be trimmed tothe slip length. The armor wires 14 are stiff and can be more readilybent back to the final position as necessary using a tubular swage tooland hammer to conform the wires 14 to the slip 50 (step 222). Theresulting wireline and bent wire profile, in isolation, is shown in FIG.20C.

As shown in FIG. 20B, at step 226, the slip cap 60 can be forced overthe wires 14 and slip 50, securing the wires 14 in an annulus 62 formedbetween the slip 50 and cap 60, also shown in FIG. 20D. The cap 60 canbe prefilled with the dielectric grease G to backfill between bentstrand wires 14. The tensile wireline connection is then complete forbearing against the uphole support of the cable head.

In FIGS. 21A and 21B, at step 228, the slip cap 60 is secured using ananchor sleeve 64, which in this embodiment is threaded to the anchorslip 50, sandwiching the slip cap 60 axially therebetween. FIG. 8Aillustrates an exploded view of a packoff assembly 40 connectedcomponent by component using complementary threaded couplings.Alternatively, as shown in FIGS. 15A and 15B, the components may beindependent, non-threaded, and when assembled, butt up against eachother and are secured together only once the closure plug nut 42 isthreaded into downhole end 36 of the packoff bore 32.

In FIGS. 21C, 22A and 22B, at step 230, the remaining layer or layers ofinner armor wires 14 extending from the anchor sleeve 64 can be trimmedoff radially down to the insulation layer 16 of the electricalconductor(s) 20. Further, at step 232, the electrical conductor 16 ofthe wireline 10 can be trimmed to the desired length.

The anchor sleeve 64 also provides a conical recess or uphole cone slip66 for the packoff bushing 70. With reference to FIGS. 22A and 22C, atstep 234 and for filing the uphole cone slip 66 and generally formaximal packoff cartridge fluid padding, a grease fitting or interiminjection tool adapter 110 can be temporality threaded to the anchorsleeve 64 and grease G pumped into and through the anchor sleeve 64 andanchor slip 50 assembly, excess grease G discharging from the anchorslip 50 at the vise 48. Fillage is confirmed as needed and visible ifthe vise 48 is temporarily loosened form the cable head 30 (step 236).

After confirmation of grease fillage, at step 238, the vise 48 can besecured again to the cable head 30 and the slip 50 reset thereto.

As shown in FIG. 23A, at step 240, the packoff bushing 70 can be slidover the wireline 10. In embodiments, the packoff bushing 70 can be madeof polytetrafluoroethylene or another suitable material. With referenceto FIG. 23C the packoff bushing 70 can be countersunk to accept thediameter of the trimmed inner armor 12, and the remainder of the bushingbore 72 fit to the diameter of the insulation 16 of the electricalconductor portion 20. The downhole end of the anchor sleeve 64 is aconcave conical recess or cone slip 66 for receiving the packoff bushing70. Shown best in FIGS. 23B and 23C, at step 242, a packing sleeve 74,having a downhole conical recess or cone slip 78 at its uphole end 76,is axially engaged with the packoff bushing 70 and can be threadablysecured to the anchor sleeve 64. The threadable packing sleeve 74includes this convex conical receiver 78 intermediate therealong forreceiving the downhole end of the packoff bushing 70. The uphole anddownhole ends of the packoff bushing 70 are a corresponding convexconical shape or other suitable shape for being axially compressed bythe uphole cone slip 66 and downhole cone slip 78 to seal with thewireline 10. Grease G can be liberally provided about the bushing 70, inthe bushing bore 72, and within the packing sleeve 74 beforeinstallation.

With reference to FIG. 10, when the packoff components are assembled,the bushing 70 is compressed axially between the conical convex faces ofthe anchor sleeve 64 and packing sleeve 74, compressing the bushing bore72 into close or compressive engagement with the wireline 10.

As shown in FIG. 24A, the insulated electrical conductor 20 is shownextending from the packing sleeve 74. A short portion of the electricalconductor 20 is shown stripped. In FIG. 24B, at step 246, a crimpedcontact or boot contact 80 is placed over the conductor 20 and crimpedin place for forming primary electrical connection 86 and leaving asocket or female contact portion 84 available at a downhole end 82thereof for releasable female/male coupling electrical coupling with thehermetically sealed secondary electrical connection 90.

At this point, if unprotected, the electrical connections 86,90 could bevulnerable to high pressure well fluid incursion along the wirelinestrands 14, as was the prior art. In this embodiment, the inner wirelinearmor 12 terminates upstream of the primary electrical connection 86.

With reference to FIGS. 25A through 28A, the boot contact 80 is housedwholly within the packoff cartridge 40 that is then sealed within thepackoff bore 32, having only a hermetically sealed female contactportion 84 extending therefrom.

In more detail and starting at FIGS. 25A and 25D, the female crimpedcontact or boot contact 80 is axially coupled with a first maleelectrical contact 104 of a feed-through connector 100, which extendshermetically through the axial connection of the balance of thecartridge components.

In FIGS. 25B and 25C, at step 248, an elastomeric boot 96 and plasticsleeve 98 are arranged about the contact 80. Also with reference toFIGS. 13D and 13E, the female contact portion 84 is concentric withinthe boot 96. While the boot 96 is elastomeric and conforms generally tothe insulation 16 about the conductor wire 20, the seal may not beperfect due to imperfections such as scalloped indents 18 formed alongthe insulating jacket 16 of the wireline 10. Accordingly, the successand efficacy of the grease pad is improved by manually adding grease Gto the boot 96 during assembly.

In this embodiment, the releasable primary and secondary electricalconnections 86,90, contact 80, and boot components are those supplied byKemlon in various forms, including a feed-through connector 100, shownhere as a single pin version. Other multi-pin connectors and similararrangements can be employed for more detailed and complex electronicenvironments. The feed-through connector 100 provides an electricalconnection through a hermetically sealed body 102 that is sealably fitto a tool bulkhead for fluid sealed, electrical pass through connection.The feed-through connectors 100 include those with differential pressureratings across the bulkhead of about 20,000 psi. The packoff cartridgebulkhead 41, formed by the closure plug nut 42, separates the wellborefluids from the downhole tool 22.

Such electrical sealing systems fall under the Duo-Seel™ (KemlonProducts) for “booted feed-through connectors”. As stated by Kemlon, asingle pin connector system consists of a feedthrough connector 100mounted in a bulkhead and a female connector (commonly referred to as aboot) 96 which plugs onto a first male contact 104. Inside the boot 96is a contact 80 which grips the metal pin on the male bulkhead connector104. The boot 96 and contact 80 are sold together as a set. An upholeend of the boot 96 is either bonded to the wire cable 20 or slips ontothe wire tightly and makes a seal on the cable 20. A downhole end of theboot 96 fits tightly on the dognut of the feed-through connector 100 andmakes a seal there also. Inside the boot 96, current passes through thewire 20, through the contact 80, and finally through the first malecontact 104. A seal between the feed-through connector 100 and the toolbulkhead 23 is most commonly made with a rubber “O” ring, but can bemade with a pipe thread or a metal ring. Kemlon's connector system iscovered by one or more of the following U.S. Pat. Nos. 4,077,261,3,793,608 and 3,898,731. A second male contact 106 of the feed-throughconnector 100 is positioned opposite the first male contact 104 suchthat is located on the other side of the tool bulkhead 23 for connectingwith electronic components of the tool 22. In embodiments, the contact106 can be a female contact.

In FIG. 26A, at step 250 and with reference back to FIG. 25D, theprimary electrical connection 86 is protectively housed in a boothousing 94 fit with a hermetically sealed secondary electricalconnection 90 having at least the first male contact 104 extendinguphole, the first male contact 104 being compatible with the female bootcontact 80 crimped to the wireline conductor wire 20. As shown, thesecondary electrical connection 90 has a downhole electrical connection,in this case the second male contact 106, located outside the packoffbore 32. As stated above, while the contact 106 illustrated as male inthis embodiment, the contact could be configured as a female connectiondepending on the adapter assembly arrangement and downhole tool 22.

Shown also in FIG. 268, the boot housing 94 aligns with the contact(s)104,106 of the feed-through connector 100. A window in the boot housing94 enables viewing of the interface of the elastomeric boot 96 and thefirst male contact 104. The plastic sleeve 98 within the boot 96 guidesthe first male contact 104 into the crimped boot contact 80 as the boothousing 94 axially approaches the packing sleeve 74 for coupling.

With reference to FIG. 27A, the length of the electrical wire 20extending from the wireline 10 had been previously trimmed for seatingthe crimped contact 80 over the first feed-through male contact 104 whenthe boot housing 94 is axially engaged with the packing sleeve 74.Similarly, the elastomeric boot 96 extends about the feed-through pininterface, providing a protective cover about the primary electricalconnection 86. As will be discussed below, the protective cover is notstrictly needed for the exclusion of well fluids as the packoff bore 32is sealed at the downhole end 36 by the packoff closure plug nut 42 andthe packoff bore 32 is filled with an incompressible grease G thatcannot be displaced despite any attempt by well fluids to encroach alongand between the strands of wireline armor 12. As above, to minimizeerror, the boot 96 can be pre-filled with grease G.

With reference to FIG. 27B, the feed-through connector 100 is sealablyfit to and secured to a downhole end of the boot housing 94. In turn,the boot housing 94 is fit with circumferential seals 92, such as at theuphole and downhole ends thereof, for sealable interface with thepackoff bore 32. When secured therein by the packoff closure plug nut 42(FIG. 29A), the feed-through connector 100 is sealed within the packoffbore 32 with the second male contact 106 extending sealably out of thepackoff bore 32 to a dry side of the cable head 30.

Turning to FIG. 28A, if the packoff assembly 40 had not already beenthreadably coupled as each component was added, the entirely of thepackoff assembly 40 can be tightened and axially compressed bytightening the boot housing 94 as against the non-rotating anchor slip50 held in the vise 48. In FIG. 28B, at step 252, the packoff assemblyis complete as a packoff cartridge 40.

As shown in FIGS. 8D and 27B, at step 254, the boot housing 94 has athreaded end 95 which can be temporarily adapted to an insertion tool Tas shown in FIG. 28A. The packoff assembly 40 can be held securely whilethe vise 48 is removed as shown in FIG. 28B (step 256). As discussedearlier, and as shown, the wireline 10 has some slack before beinginstalled to the packoff bore 32. There is sufficient axial travel inthe wireline 10 for the freed anchor slip 50 to now be axially insertedinto the packoff bore 32 and all the way uphole to engage the upholestop 44. Grease G can be applied to the packoff assembly 40 prior toinstallation in the packoff bore 32.

As shown in FIG. 29A, at step 260, the closure plug or nut 42 is fitthreadably to the downhole end of the packoff bore 32. To avoid the nut42 from projecting axially from the packoff bore 32, the nut 42 isaxially sized for the packoff bore 32. The nut 42 can be fit with a facewrench interface, here shown as an array of pin holes 43 for drivableconnection with a comparable pin wrench. As shown in FIG. 29B, the pinwrench permits retention of the packoff assembly 40 within the packoffbore 32.

With reference to FIG. 30A, at step 262, grease G is first provided tothe downhole end of the packoff assembly 40. Grease G flows through thecable head 30 and into the packoff bore 32 to fill the packoff bore 32from the downhole end 36 towards an uphole end 34. To ensure theelectrical connections 86,90 are protected from wellbore fluid ingress,the electrical connections 86,90 and surroundings are padded or filledwith grease G. As shown in FIG. 301, the boot housing 94 can then bechecked to ensure proper grease fillage.

Also with reference to FIG. 14, at step 262, a grease fitting 110 is fitto a grease port 108 of the termination sub 24 at about the downhole end36 of the packoff bore 32. Alternatively, as shown in FIGS. 80, 13A, and138, the packoff assembly 40 is fit with grease galleries 112 instringers 113 for receiving grease G from the fitting 110 into the bore32 and first directing the grease G at least downhole along a peripheryor passages 112 of the assembly 40 to the downhole end 36 of the packoffbore 32 before the grease G proceeds toward the uphole end 34. As aresult, in both embodiments, grease G fills the bore 32 from thedownhole end 36 and migrates towards the uphole end 34, displacing anyremaining voidage and placing the incompressible grease G within thebore 32. As shown in FIGS. 8D and 14, the boot housing 94 can also befit with an uphole port 114 for discharging grease G along the packoffassembly and bore interface for elimination of voids therealong. Agrease gallery 112 can connect the grease port 108 with the uphole port114. In operation, pressurized well fluid cannot migrate into thepackoff bore 32 from the uphole end 34 as the grease G cannot bedisplaced downhole.

As seen in FIG. 3, a grease plug 109 can be used to fluidly seal thegrease port 108 when not in use.

After packoff assembly 40 has been secured inside the packoff bore 32 ofthe cable head 30, the adapter assembly 26 can be connected to the cablehead 30 and the now assembled termination sub 24 can be connected to thesensor tool 22.

Embodiments of the invention for which and exclusive property orprivilege is claimed is defined as follows:
 1. A cable head terminationsub located between a wireline having wireline armor and an electricalconductor therealong, and a downhole tool, the termination subcomprising: a cable head having a structural body, the body having apackoff bore extending therethrough from an uphole end of the body to adownhole end of the body, the downhole end adapted for releasablecoupling with the tool; and the packoff bore configured to releasablyreceive a packoff assembly therein and having an uphole stop defining anentrance bore, and a downhole opening, the entrance bore having anentrance diameter smaller than a bore diameter of the packoff bore andsized for receiving the wireline therethrough; a closure plug forsealing the downhole opening and fluidly isolating the packoff bore fromthe downhole tool; and a grease port located on the body forintroduction of dielectric grease to the packoff bore; and wherein thepackoff assembly comprises an uphole anchor slip having a slip bore forreceiving the wireline therethrough and a slip interface for securingthe wireline armor thereto, the anchor slip bearing against the upholestop; a packoff bushing downhole of the anchor slip having a bushingbore for receiving the wireline therethrough; a boot contact attached tothe wireline conductor to form a primary electrical connection; and afeed-through connector having a first contact compatible with the bootcontact and coupled thereto to form a secondary electrical connection,and a second contact for electrical connection with the downhole tool;and when the packoff assembly is sealed within the packoff bore with theclosure plug, the grease within the packoff bore prevents fluid fromreaching the first and second electrical connections.
 2. The terminationsub of claim 1, wherein the grease port directs grease to the downholeend of the packoff bore for backfilling the packoff bore with the greasefrom the downhole end toward the uphole end.
 3. The termination sub ofclaim 1, wherein the packoff assembly first comprises a boot housinghaving a downhole end sealably supporting the secondary electricalconnection at the closure plug, an uphole end for receiving the primaryelectrical connection, and a boot having an uphole boot end fitconcentrically about the wireline conductor and the boot contact and adownhole boot end for releasably receiving the first contact when thefirst contact is coupled with the boot contact, the boot residing withinthe boot housing.
 4. The termination sub of claim 3, wherein the boothousing has at least a first grease gallery adapted to direct injectedgrease from the grease port at least downhole to the downhole end of thepackoff bore.
 5. The termination sub of claim 3, wherein the boothousing further comprises a circumferential seal for creating a sealwith the packoff bore uphole of the grease port for preventing greasefrom travelling uphole between the boot housing and packoff bore.
 6. Thetermination sub of claim 3, wherein the boot housing has at least asecond uphole gallery adapted to direct grease toward the uphole end ofthe packoff bore and along an annulus defined between the packoffassembly and the packoff bore.
 7. The termination sub of claim 6,wherein the boot housing further comprises an uphole port fordischarging grease along the annulus.
 8. The termination sub of claim 1,wherein the uphole stop is removably coupled with the packoff bore.
 9. Amethod of sealing a wireline in a cable head located between thewireline and a downhole tool, the wireline having wireline armor and anelectrical conductor therealong, the method comprising: inserting thewireline through an uphole stop of a packoff bore of the cable head andout of a downhole opening of the packoff bore; positioning an anchorslip about the wireline; bending one or more wires of the armor over aslip interface of the anchor slip and securing the one or more wires tothe anchor slip; positioning a packoff bushing about the wirelinedownhole of the anchor slip; electrically connecting the conductor ofthe wireline with a boot contact to form a primary electricalconnection; coupling a first contact of a feed-through connector withthe boot contact to form a secondary electrical connection; insertingthe first electrical and second electrical connections into a boothousing, the anchor slip, packoff bushing, and boot housing forming apackoff assembly; inserting the packoff assembly into the packoff bore;sealing the downhole opening of the packoff bore with a closure nut; andintroducing grease to the packoff bore such that grease fills thepackoff bore from the downhole end to encompass at least the primaryelectrical connection and the secondary electrical connection.
 10. Themethod of claim 9, further comprising the step of securing the upholestop within the packoff bore.
 11. The method of claim 9, wherein thestep of introducing grease to the packoff bore further comprisesdirecting the grease first to a downhole end of the packoff bore andthen toward an uphole end of the packoff bore.
 12. The method of claim9, further comprising the step of applying grease to one of the anchorslip, packoff bushing, and boot housing, or a combination thereof, priorto sealing the downhole opening of the packoff bore.
 13. The method ofclaim 9, wherein the step of inserting the first and second electricalconnections into a boot housing further comprises inserting the firstand second electrical connections into a boot and inserting the bootinto the boot housing.
 14. The method of claim 9, wherein the step ofpositioning the anchor slip further comprises securing a vise to thewireline downhole of the downhole opening and coupling the anchor slipto the vise, and step of inserting the packoff assembly into the packoffbore comprises first removing the vise from the wireline.
 15. The methodof claim 9, wherein grease is introduced to the downhole end of thepackoff bore.
 16. The method of claim 9, wherein the grease isintroduced at an axial location uphole of the downhole end of thepackoff bore, the grease flowing toward the downhole end via at least afirst grease gallery.
 17. The method of claim 16, further comprisingdirecting the grease toward the uphole end from the downhole end via atleast a second grease gallery.
 18. A packoff assembly for use within apackoff bore of a cable head to connect a wireline having wireline armorand an electrical conductor therealong with a downhole tool, comprising:an uphole anchor slip having a slip bore for receiving the wirelinetherethrough and a slip interface for securing the wireline armorthereto; a packoff bushing having a bushing bore for receiving thewireline therethrough; a boot housing having a feed-through connectorsealably supported therein, the feed-through connector having a firstcontact compatible with a boot contact attached to the wirelineconductor and a second contact for electrical connection with thedownhole tool; and at least a first grease gallery formed in the boothousing and adapted to receive grease injected into the packoff bore anddirected the grease towards a downhole end of the boot housing.
 19. Thepackoff assembly of claim 18, wherein the boot housing defines an upholeport in communication with at least a second grease gallery and adaptedto direct grease toward an uphole end of the packoff bore and along anannulus defined between the packoff assembly and the packoff bore. 20.The packoff assembly of claim 18, wherein the boot housing comprises aboot having an uphole boot end fit concentrically about the wirelineconductor and the boot contact a downhole boot end for releasablyreceiving the first contact when the first contact is coupled with theboot contact, the boot residing within the boot housing.